All we can see outside in the dark are moving, ghostly fronds – foliage bleached by the passing light spilling from our boat, nodding in the gusting winds above the lap of water. We’re on the river at night. We can’t see where we’re going, and we’ve entrusted our safety to a group of people with the seedy, ingratiating collective name of Earnest Cox. Things look bleak.

He’s greeted by laughter. It’s all far, far too English for any of that: those nodding leaves we’re passing are in quiet Gloucestershire, and the River Severn isn’t winding us towards the heart of darkness… not unless Bristol’s having a really bad Saturday night. The double-decker boat we’re riding – the MV King Arthur – has been hired from the National Waterways Museum, and in under four hours we’ll have looped back to its safe berth in Gloucester. On the way, we’ll be enjoying a self-propelled music bash featuring the aforementioned Coxers and a little circle of related bands from Gloucester and London. There’s even a raffle. Cosy.

Had we set out a little earlier in the summer, and during the day, it would have been picnics and beer all round by now. As the red and gold lights of a jolly riverside pub bob past like a luminous Johnny Walker bottle, it’s clear that any actual weirdness will need to be handled by the bands. Crammed onto chairs on the makeshift band stage wedged into the top deck, Datapuddle do what they can. Alex Vald (who once played filthy guitar for Dream City Film Club) cradles an electric mandolin across his chest like a sulking cat. When not distractedly plucking and strumming at it as if he were plucking a chicken, his hands dart restlessly towards a litter of electronic gizmos on a table: a virtual theremin, a cheap sequencer, a plastic voice-changer and other bits of toy-box guts. Stephen Huddle plays sketchy acoustic guitar and pushes broken murmurs and mumbles of song up into Alex’s cobwebs of sound.

Datapuddle at The Cox Cruise

What ultimately emerges is a lo-fi cat’s-cradle of strung-together and slightly strung-out elements. Tidal dub; debris and dusty notes swept out of an Irish-American bar; bits of memory and reaction scattered like dandruff – all glued by static electricity and misfiring synapse energy to the guitar strings of a long-fried singer-songwriter. “Here’s a little sea shanty,” says Stephen brightly. A water-blip of electronics merges with a Lloyd Cole chug of guitar, rocking it on its rhythmic base. Alex buzzes a harmonica into an overlapping backwards loop, transforming it into a reversed melodica.

On the next song, trip-hop snare-drum smoke merges with psychedelic space whisper like the first skunked-out collision between Portishead and Hawkwind. Alex’s mandolin maintains a relentless, disappearing clang like a freight train bell, while Stephen mutters like Tom Waits ruffled from deep sleep. Peril – another shaggy-dog shanty written especially for tonight – namechecks the Severn amidst its steam-train chunter of knocks, old-school electro breaks, and harmonica rasps. “Don’t buy the brown acid,” Stephen sings, channelling up the confusion of a different party as ours sways cheerfully along the river.

Datapuddle come to a purring end with lashings of electric theremin wibble and a lengthy musical chew on a genuine melodica which has surfaced from their box of battered goodies. Watching them was like watching someone scrabble a shack together out of estuary trash and flotsam. In its way, it was just as raw and triumphant.

Paddy McCarthy & Michael J. Sheehy at The Cox Cruise.

While the upstairs audience return to conversation and shore-spotting, Michael J. Sheehy and Paddy McCarthy are down below decks mopping up the leftovers (along with any beer that’s available). Cuddling a pair of honey-blonde acoustic guitars, the brothers from St Silas Intercession (and, previously, Dream City Film Club) have wedged themselves into a corner to hammer out rough’n’ready London-Irish punk blues as brutal as paving stones and hard-luck sneers. Eventually they’re joined by a wandering harmonica player and by a growing crowd of boozy party stragglers. Before too long, the corner turns into an enthusiastic trash-music shebeen (staggered over the changeover times between the acts upstairs) during which everyone’s treated to rattling, spat-out’n’spattered takes of the songs from the debut St Silas EP, starting with the vicious roar of You Don’t Live Here Anymore.

St Silas Intercession’s music is a London echo of the brutally direct and bluesy garage noise still spilling out of Detroit (and all of the little Detroits that have sprung up in the wake of Jack White or The Dirtbombs). Venomous as a dirty flick-knife and as blunt as masonry nails, it’s some way down the evolutionary tree from the corrupted sophistication of Sheehy’s recent songwriter albums, or even from the trawling sleaze of his old work with Dream City Film Club. Obviously the man himself couldn’t give a shit about all that: judging by the twinkle in his eyes and in Paddy’s, as they face each other off over sprawling riffs and hollers, they’ve rarely been happier with their music than now.

Paddy McCarthy at The Cox Cruise.

The brute-blues meanness of Get My Share has a good hard whiskey sting to it; as does the defiance of Caravan Rock (“me and my kids and their mum, / living in a caravan, moving on, moving on…”). A lacerating spurt through All About The Money sets people bobbing, scrambling and bouncing as well as a seven-and-a-half foot deck ceiling will allow. But as Paddy’s permanent goofy cartoon grin indicates, the St Silas brothers never take themselves too seriously. “It’s always about the money!” Michael protests, through a cheap megaphone. His voice suddenly jumps tracks from Louisiana bawl back through his London grit to an ‘EastEnders’ stage-Cockney. “You sla-a-a-g!”

Back upstairs, a dirty blonde in a cute plush cap is hammering a comradely nail into Mr Sheehy’s coffin. “Michael slags me off in his songs, and I slag him off in my songs,” explains Charlie Beddoes. Then she bowls us the rapaciously scornful putdowns of Vitriolic Alcoholic which kerb-kicks a snarling addict with a series of offhanded verbal wallops, culminating in “do I look like I give a toss? / It’s not my problem, not my loss.” It’s good to have friends.

The determined, diminutive Charlie is both the figurehead and the core of the shifting cult-of-personality that calls itself Charlie Says. Tonight, they’re three boot-babes and a moll-boy. Backed up by sidekick Ben Fisher’s car-crash guitar and by Lian and Kim Warmington’s ice-diva backing vocals and cool basilisk stares, Charlie plucks a remarkably articulate bass, sings like a breezeblock with lipstick and thuds out middle-weight girlpunk. Not short of charisma, Charlie holds the audience in the palm of her hand. The trouble is, she then rolls them around as if she doesn’t quite know what to do with them.

There’s a big difference between true punk and mere punk-ertainment, and Charlie Says wander a bit too close to the latter end of the scale. While Charlie’s former background in hip-hop art-rockers Rub Ultra is promising, discovering that both she and Ben are recent refugees from the touring band of tech-rocker Martin Grech pokes some suspicious holes in their lo-fi rebel stance. It just makes their music seem a little contrived. Not that the songs always help: It’s All About The Music is just another me-and-my guitar anthem, and Hey Leadfinger, Why You Gotta Keep Putting Me Down? is a foray into garage-blues which is far less interesting than its title is.

What pulls the band up out of fun-punk poseur-world are Charlie’s bright flickers of blunt humour and determination. The girlpower swagger of Venus Envy suddenly flings out “if the balls are in our court, then at least we have some,” while This Is Not My Story claims “whichever way it lands, my heart will keep on beating.” Little gems of lead-pipe wit and guts like this are what will make Charlie Says special; not desperate attempts to hitch onto whichever punk or garage soul flits past next. For the rest of the evening, I see Charlie perched here and there around the boat – beaming with life, always as if on the verge of delivering another breezy wisecrack. Let’s have more of that.

For all their efforts, Charlie Says don’t make me want to riot. Ghosting do… but I’d be rioting on their behalf. Five more minutes of hearing boozy party blabber drown out their beautiful, beautiful songs and I’d be flinging bottles around myself. Ghosting are heartbreakingly soft – as vulnerable and resilient as fresh grass bending underfoot. Unlike any other band this evening, they create little pockets of pure songcraft which you need to crane your head into to find out what’s going on.

Upfront, Dan Pierce picks out gentle acoustic guitar arpeggios which ride up into the atmosphere like thermals, and lets his voice follow suit. In the corner, wedged into a little cage of half-drumkit, laptop and miniature keyboard, George Moorey handles the rest. Intent and anxious-looking, he peers at his screen like a nervy microbiologist watching a virus proliferate. In fact, he’s just making sure that the sounds arrive on time – making tiny triggering adjustments to a mouse, reaching out one hand to roll off a gentle peal of Blue Nile piano, or swivelling to make precise soft taps on cymbal and snare with the single drumstick he holds in his other hand. It’s like watching someone play a one-man-band suit and conduct an orchestra at the same time. Yet even more impressive than this deft and diffident juggling act are the way Ghosting’s songs pool in the atmosphere – gradually, quietly filling up the space.

Dan’s big genial frame contains a songwriter’s spirit of rare and seductive delicacy. Faced with a chattering crowd, he simply shifts his guitar in his hands and sings soft, warm and open… and slowly the chatter drains away as the spell begins to work. Gently, Ghosting explore topics spanning all the way from frayed love songs (Your Love Don’t Make Sense) through thoughtful disillusion all the way to ending up being fingered as a murder suspect (Someone At The Door). Hopefully not as a natural progression – but if it was, you’d suspect that they’d’ve illustrated even that story with colossal and convincing sensitivity.

By the time Ghosting are midway through the exquisite, naked plea of I Want You To See Me, the crowd is hushed and half of them are hooked. Dan’s flexible and heartfelt singing – mostly a feather on tremulous breath, but rising to a swoony peak of intensity – sometimes recalls Mike Scott or Robert Forster at their very softest. In a fey, English, breathy way, he even has flashes of the fluttering abandonment of a Van Morrison or an Aaron Neville. Like them, he’s singing songs of real people grasping out at the intangible – unsure of what to believe on Anything That Might Be True, or “waiting for the one thing which really might have been some help,” on Good Year, only to wait in vain. Intangible desires, tangible heartaches. They’ll probably rise like damp rather than rockets, but I suspect that within a few years Ghosting will be very important to a lot of people.

Having put the whole cruise together in the first place, Earnest Cox get a well-deserved heroes’ welcome once they arrive onstage. They respond with perhaps their most energetic and assured set to date. It’s the third or fourth time I’ve caught the Cox, over a time when I’ve watched their sturdy intelligence getting to grips with lacing together their multiple influences. It’s taken a while for their mixture of old Memphis R’n’B, ’60s lad-rock, ’80s indie textures and prowling street poetry to gel.

Tonight it does with a vengeance. Hello Stranger sweeps out of the gate with a swagger of rogue testosterone coupled with a smart and beady eye, as Cox singer La Windo immediately takes on the audience with his particular blend of strut and twice-burned wariness. Perhaps it’s recent honeymoon rejuvenations or perhaps it’s the side effects of squabbling over their current recordings, but Earnest Cox are smouldering tonight. Still looking like a disparate houseful of mature students (the band’s a bewildering range of types from motherly to mysterious, from rogue to stockbroker) they continue to draw on what’s in them already rather than trying to squeeze themselves into an image.

The rhythm section used to be little more than agreeably white’n’slightly-funky: now it’s moving towards a lubricious slippery groove, with bass player/occasional MC Simon abandoning cheese and cheeriness to join drummer Shane in seriously flexing the pocket. Nicola parachutes in flights of piano, springs of Booker T. Hammond organ or splurges of synth when she needs to, while Marc buries himself in the middle of the band, cooking up lightly-textured mats of funky guitar texture to fly blurs across the gaps.

Up front, where you’d expect to find a preening Rod Stewart lookalike, La continues to prowl like a Gloucester merging of Shaun Ryder and Lou Reed, delivering his narratives of edgy small-town life like the most restless man in the pub and shaking his percussion as if testing the heft of a throwing knife. He looks pretty handy: yet the Cox don’t exactly trade on casual violence, even when La hurls out scathing fighting talk on You’re Not Fit To Lick (The Shit From My Shoes).

Rather, they seize on restlessness in general, whether it’s randiness, boredom, the unease as your parents age towards death, or the bumps in love’s road. There’s swagger, vengeance and one-upmanship aplenty in songs like Two Can Play At That Game, Baby and Scratching The Same Old Itch: yet in spite of this Earnest Cox’s songs are about survival if they’re about anything. No More Happy Endings treads the ashes of hopes and securities with the dogged, battered trudge of someone who’s had the knocks, has sagged, but won’t go down yet.

The Cox’s musical cockiness almost makes them part of that line of lad’s bands dipping in and out of pubs, taverns and speakeasys (and finally Royal Command performances). Yet the way the bruises on the songs never entirely fade (and the way that La quietly retreats into himself, gaze distracted, mid-song) hints at a band who’ve accepted, even embraced, the dragging baggage of personal history rather than saturating themselves in adolescent posing. Marc’s refusal to play the role of the strutting guitar stud (keeping his back almost entirely turned to La and the audience as he brews up his noises) confirms it and heightens the internal dignity beyond the Cox’s miscellaneous looks.

Perhaps it’s this mixture of getting by, getting on and getting on with it even within limited horizons that makes Earnest Cox local heroes on the Gloucester scene. The familiar tastes of that stew of pop ingredients they serve it up with, plus their band’s anti-glorious English universality and their bumpy everyman charisma should win them friends around the country, whether or not they bring their boat with them.

As the Cox set hits its climax, we look up and find ourselves back in the Gloucester lock. Hometime, Charlie.